SprawdzNumer.pl is a public directory for checking and assessing Polish telephone numbers. It helps people find out who may have called, review other users’ reports, and make a more informed decision before calling back. Visitors can search by phone number or browse the directory by prefix. The site also displays recently commented, frequently viewed, and newly listed numbers, along with information about number ranges and their assigned operators.

Its database contains millions of numbers and information on Polish numbering ranges and operators. For each lookup, the register compares the number with the national numbering plan to indicate the relevant range, operator, and type of number. Reputation verdicts are based on reports from people who received calls from that number. When there are too few reports to support a conclusion, the site indicates that information is unavailable rather than guessing. Users can contribute their own rating and a short comment, helping others recognize potentially unwanted calls, spam, or scams.